Video compression refers to reducing the quantity of data used to represent video content while reducing the quality as little as possible.
Digital video requires high data rates—the better the picture, the more data is ordinarily needed. Thus, powerful hardware and considerable bandwidth are normally required when video is transmitted. However, much of the data in video is not necessary for achieving good perceptual quality because it can be easily predicted. For example, successive frames in a movie rarely change much from one to the next—this makes video well suited for compression. Video compression can make video files far smaller with little perceptible loss in quality. For example, DVDs use a video coding standard called MPEG-2 that makes the movie 15 to 30 times smaller while still producing a picture quality that is generally considered high quality for standard-definition video. Without proper use of data compression techniques, either the picture quality for a given video would look much worse, or the video would require more disk space.
Video is essentially a three-dimensional array of color pixels. Two dimensions serve as the spatial (horizontal and vertical) directions of the moving pictures, and one dimension represents the time domain. A frame is a set of all pixels that correspond to a single point in time. Essentially, a frame is the same as a conventional still picture.
Video data contains spatial and temporal redundancy. Similarities can thus be encoded by merely registering differences within a frame (spatial) and/or between frames (temporal).
Better compression techniques allow, for instance, a service provider to offer additional or new services to customers; in some cases better compression may allow service providers to offer service to new customers, who could not be served otherwise. Thus, there is a need for an improved system and method for improved video compression efficiency.